This invention relates to a hermetically closed fluid bag with an integrally welded drinking spout or dispensing spout. Fluid bags with all types of closures are known in many variants. The bags may be manufactured from animal skins, intestines, from rubber or also from plastic film material. Fluid bags of plastic film material are particularly practical, since they are lightweight, may assume different shapes and thus may be carried and stored much more easily, and when empty, do not take up much space, and finally because they may be disposed of without any problem. Since such fluid bags of plastic films are mostly envisaged for disposable consumption, the associated closure must be able to be manufactured in a very inexpensive manner. In medicine, such bags are also applied for preparing infusions. These bags must also provide an integrity guarantee. The solutions known until now however, are very extensive. The closures consist of several parts and are therefore expensive. The solutions for the integrity guarantee are complicated and require much effort with regard to the manufacture.